Subversion Repositories raytrac

library ieee;

use ieee.std_logic_1164.all;

entity shftr is

        port (

                dir             : in std_logic;

                places  : in std_logic_vector (3 downto 0);

                data24  : in std_logic_vector (23 downto 0);

                data40  : out std_logic_vector (39 downto 0)

        );

end shftr;

architecture shftr_arch of shftr is

        component lpm_mult

        generic (

                lpm_hint                        : string;

                lpm_representation      : string;

                lpm_type                        : string;

                lpm_widtha                      : natural;

                lpm_widthb                      : natural;

                lpm_widthp                      : natural

        );

        port (

                dataa   : in std_logic_vector ( lpm_widtha-1 downto 0 );

                datab   : in std_logic_vector ( lpm_widthb-1 downto 0 );

                result  : out std_logic_vector( lpm_widthp-1 downto 0 )

        );

        end component;

        signal splaces  : std_logic_vector (8 downto 0);

        signal sdata24  : std_logic_vector (26 downto 0);

        signal sdata32  : std_logic_vector (31 downto 0);

        signal sresult  : std_logic_vector (53 downto 0);

begin

        process (places(2 downto 0))

        begin

                case places(2 downto 0) is

                        when "000" => splaces <= "000000001";

                        when "001" => splaces <= "000000010";

                        when "010" => splaces <= "000000100";

                        when "011" => splaces <= "000001000";

                        when "100" => splaces <= "000010000";

                        when "101" => splaces <= "000100000";

                        when "110" => splaces <= "001000000";

                        when others => splaces <="010000000";

                end case;

        end process;

        sdata24(26 downto 24) <= (others => '0');

        process (dir,data24,sdata32)

                variable offset : integer;

        begin

                if places(3) ='1' then

                        offset:=8;

                else

                        offset:=0;

                end if;

                data40 <= (others => '0');

                if dir='1' then --! Corrimiento a la derecha

                        for i in 23 downto 0 loop

                                sdata24(i) <= data24(23-i);

                        end loop;

                        for i in 31 downto 0 loop

                                data40(i+8-offset)  <= sdata32(31-i);

                        end loop;

                else

                        sdata24(23 downto 0)     <= data24;

                        for i in 31 downto 0 loop

                                data40(i+offset)        <= sdata32(i);

                        end loop;

                end if;

        end process;

        the_shifter:

        for i in 2 downto 0 generate

                shiftermultiplier: lpm_mult

                generic map ("DEDICATED_MULTIPLIER_CIRCUITRY=YES,MAXIMIZE_SPEED=9","UNSIGNED","LPM_MULT",9,9,18)

                port    map (splaces,sdata24(i*9+8 downto i*9),sresult(i*18+17 downto i*18));

        end generate;

        sdata32(31 downto 27) <= sresult(49 downto 45);

        sdata32(26 downto 18) <= sresult(44 downto 36) or sresult(35 downto 27);

        sdata32(17 downto 09) <= sresult(26 downto 18) or sresult(17 downto 09);

        sdata32(08 downto 00) <= sresult(08 downto 00);

end shftr_arch;